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Re: PFC current load



Original poster: "Jonathan Peakall by way of Terry Fritz <twftesla-at-qwest-dot-net>" <jpeakall-at-mcn-dot-org>

Terry,

Thanks a bunch, with about 300uf max PFC for my 15/120 I'll defintly go the
relay route, I have a 15 amp ice cube laying around. I appreciate you
reducing the formula to a ratio for me! Another PFC question, I have multi
value caps, 20/36uf, and they have three tabs, marked A,B,C. Is there a
standard for the internal arrangement of this type of cap? My meter only
reads up to 2uf, so I would have to string em all together to figure out
which is which.

Thanks again!

Jonathan Peakall

> If you place a cap directly across the AC line, like for a PFC cap, the
current
> is:
>
> I = Vac x (2 x pi x F x C)
>
> I is the RMS current
> Vac is the RMS line voltage
> pi = 3.14159...
> F = 50 or 60 Hz.  AC line frequency
> C is the capacitance in "Farads"
>
> So a 100uF cap is:
>
>  I = 120 x (2 x 3.14159 x 60 x 100e-6) = 4.52 Amps RMS
>
> It is proportional so a 50uF cap is 2.26 amps and a 200uF cap is 9.04
amps.
>
> Cheers,
>